I found the Ref1 to give a vaccum seal which is uncomfortable and also messes up its sound. While on the 1Plus2 I get a perfect seal without such issue. The better the fit with the 1Plus2 the better its overall sound, especially its bass. With the Ref 1 too much of a seal and the bass appears to be a bit boomy depending on the tracks. Still too much bass for my tastes overall.